25% Levy on Profits Shifted Abroad May Run Afoul of International Treaties

LONDON—The British government detailed plans Wednesday for a new 25% tax on profits of multinational technology and other companies it says are avoiding paying tax—a move that has prompted complaints from business groups and warnings from tax specialists that it could conflict with international tax treaties.

Big U.S. technology companies like Facebook Inc. and Google Inc., along with other multinationals, have come under fire from British lawmakers for the relatively small corporate tax they pay in Britain in relation to...